IRLF 


B    3    flS3 


TREES   FOR   TOWN  AND  CITY   STREETS 

By 

F.  L.  Mulford 
FARMERS1  BULLETIN  1E08 
U.S.D.A 


FORESTRY 
;  LIBRARY 


Farmers' Bulletin    1208 

United  States  Department  oF Agriculture 


TREES 


IMP 


>  LIBRARY    , 


ONLY  vigorous  trees  that  will  withstand  the  ad- 
verse conditions  of  a  city  should  be  planted  on 
its  streets. 

The  habit  of  growth  should  be  suited  to  the  width 
of  the  street,  and  the  foliage  should  be  of  a  pleasing 
texture. 

Trees  that  bear  showy  flowers,  fruits,  or  nuts  are 
usually  not  desirable  for  street  planting.  Some  trees 
are  also  objectionable  because  their  roots  penetrate 
defective  sewers;  others  because  they  have  a  tend- 
ency to  heave  sidewalks. 

Oaks  are  probably  more  generally  satisfactory  for 
street  planting  than  any  other  group  of  trees,  fol- 
lowed closely  by  elms  and  sycamores. 

Palms  do  not  make  good  shade  trees,  though  some- 
times appropriate  for  formal  effects.  The  silver  and 
ash-leaved  maples  and  the  poplars  are  not  often 
satisfactory. 

This  bulletin  describes  the  principal  trees  that  are 
used  for  street  planting  in  the  United  States. 


Contribution  from  the  Bureau  of  Plant  Industry 

WM.  A.  TAYLOR,  Chief 
Washington,  D.  C.  March,  1922 


TREES  FOR  TOWN  AND  CITY  STREETS. 

F.    L.    MULFOBD, 
Horticulturist,  Office  of  Horticultural  and  Pomological  Investigations. 


CONTENTS. 


Kinds  of  trees  suitable  for  streets-- 
Qualities necessary 

Trees*  for  different  regions 

Trees  for  special  purposes 

Descriptions  of  street  trees 

Acacia 

Ailanthus 

Ash 

Camphor 

Chinaberry 

Elm 

Eucalyptus 

Ginkgo 

Hackberry 

Honey  locust 1 


Page. 
3 
3 
6 
11 
11 
11 
13 
13 
14 
15 
15 
17 
18 
19 
20 


Descriptions  of  street  trees — Contd. 

Horse-chestnut * 

Linden 

Locust 

Magnolia 

Maple 

Oak 

Palm 

Pepper  tree 

Poplar 

Rubber  tree 

Silk  oak 

Sweet  gum 

Sycamore 

Tulip  tree 


Page. 

21 
21 
22 
22 
22 
26 
31 
35 
35 
37 
37 
37 
37 
40 


SUCCESS  in  tree  planting  on  town  and  city  streets  depends  upon 
three  main  factors — proper  conditions  for  growth,  timely  and 
intelligent  care,  and  selection  of  proper  varieties.  The  need  of  trees 
on  city  streets  and  their  care  are  discussed  in  another  bulletin;1  in 
this  are  indicated  the  kinds  of  trees  suited  to  different  types  of  streets 
and  to  different  regions. 

KINDS  OF  TREES  SUITABLE  FOR  STREETS. 

QUALITIES  NECESSARY. 

A  tree  must  be  adapted  to  the  climate  and  to  .the  soil  on  which  it  is 
to  be  grown.  For  use  under  city  conditions  it  must  have  healthy 
foliage  that  withstands  dust  and  smoke  and  a  root  system  not  easily 
affected  by  unusual  soil  conditions,  by  restricted  feeding  areas,  or  by 
root  pruning  when  street  improvements  are  made.  The  top  should 
be  in  proportion  to  the  width  of  the  street  upon  which  it  is  used,  and 
it  should  be  rather  high  headed  or  easily  trained  to  that  form  and 
of  open  growth. 

Of  only  a  little  less  importance  is  the  character  of  the  foliage 
masses,  whether  dark  or  light,  heavy  and  somber  or  open  and  airy, 
and  also  whether  they  have  vivid  autumn  colorings.  Only  in  the 

1  See  Farmers'  Bulletin  1209,  "  Planting  and  Care  of  Street  Trees." 


r<  1208. 


most  southern  parts  of  the  country  and  in  western  California  should 
evergreen  trees  be  considered  for  street  planting,  and  then  only  the 
broad-leaved  evergreens,  such  as  magnolias  and  live  oaks.  Where 
there  is  lack  of  sunshine  in  winter,  due  to  short  or  cloudy  days,  it  is 
desirable  to  admit  all  the  light  possible  by  using  only  deciduous 
trees. 

In  all  sections  trees  differ  greatly  in  the  time  when  they  put  out 
their  leaves  in  the  spring  and  lose  them  in  the  fall. 

Table  I  shows  some  of  these  differences  in  the  coloring  and  the 
dropping  of  fall  foliage. 

TABLE  I. — Comparison  of  the  time  when  the  leaves  of  various  kinds  of  trees 
change  color  and  drop  in  the  fall,  based  upon  observation*  made  at  Wash- 
ington, D.  C. 

(The  number  of  years  in  which  observations  were  made,  upon  which  the  percentages  shown  are  based, 
is  indicated  by  the  figure  in  the  small  circle  at  the  left  of  each  percentage  recorded.] 


Variety. 

Percentage    of 
leaves  dropped. 

Color  of  autumn  foliage. 

Percentage    of 
leaves    colored 
other  than  green. 

Mid- 
October. 

Last,  of 
October. 

Mid- 
October. 

Last  of 
October. 

Red  oak 

®      1 
®    68 
®      2 
©    50 
®    70 

®      5 

®    90 
®    10 
®    72 
®    86 
®    53 
®    18 
®    13 
®      7 
©    35 
®    85 
®    40 
®    45 
®    14 
®    64 
®    60 
®    44 
©  100 
®    85 
©    31 
®    77 
®    53 
©    10 
®    80 

Red  and  bronze 

®      5 
©    28 
@    50 
®      5 

§30 
75 
100 

Pin  oak  

..      do  . 

American  elm  

Dead  yellow 

English  elm  

Yellow. 

Whiteash  

.do. 

®    90 
®    45 



Bass  wood..  . 

Brown  edge 

Linden 

Yellow 

®      0 
@    30 
©      0 
®      5 

®  100 
©    50 
®    20 
©      0 
®    88 
®    50 
®    21 
©      0 

850 
40 

Sycamore  

115 
2 
2 
65 
20 
8 
8 
43 
13 
80 
23 
15 
60 

Brown 

London  plane.  .  . 

Ginkgo  

Yellow 

®    90 

Sweet  gum  

Red.. 

Tulip  tree  

Yellow 

©  100 
®    75 
®    90 
®    10 
®  100 
©  100 
©    90 

Horse-chestnut  .  . 

Brown  edge 

Red  maple  

Red.. 

Norway  maple  

Yellow 

Sugar  maple. 

Yellow  and  red 

Black  maple  

do  .. 

Silver  maple..      . 

Yellow 

Box  elder  

Eloney  locust  

®      0 

Black  locust 

Yellow 

©      8 
™ 

©     10 

Carolina  poplar  

Lombardy  poplar  

Sycamore  maple  

Kentucky  coffee  tree  

Koelreutena  

©    SO 
©    10 
©    10 
®    30 

®  100 
®    80 
®    10 
®    40 

®      0 
©      3 

Swamp  white  oak  

Whiteoak  

®      0 
©      0 



Englishoak  

Narrow  streets  should  be  planted  with  tall  slender  trees  (fig.  1) 
or  sometimes  with  small  trees.  Broad  streets  may  be  planted  with 
spreading  trees  (figs.  2,  7,  9,  and  19),  or,  if  provided  with  a  central 
parking  space,  with  moderate-sized  trees  in  the  center  and  on  the 
sides,  or  with  trees  on  the  sides  suited  to  the  space  and  formal  trees 
in  the  center.  (Fig.  3.) 

As  a  rule,  trees  native  to  the  locality  that  have  been  successfully 
grown  in  other  cities  should  be  given  the  preference.  When  a  choice 


Trees  for  Todui'  Witt  Cttij 

must  be  made  between  untried  native  trees  and  those  tested  in  a  city 
or  town  under  different  soil  or  climatic  conditions,  it  is  better  to  give 
the  native  trees  the  first  trial.  Many  promising  native  trees  have  not 
been  planted  on  a  sufficiently  large  scale  or  under  sufficiently  varied 
conditions  to  demonstrate  their  real  value  for  street  planting  over 
any  considerable  area.  Many  of  the  trees  mentioned  in  this  bulletin 
may  prove  valuable  far  beyond  the  areas  for  which  they  are  sug- 
gested. The  bur  oak,  the  swamp  white  oak,  the  scarlet  oak,  the 
chestnut  oak,  the  white  oak,  the  sour  gum,  and  others  may  be  found 
on  further  trial  to  be  as  valuable  as  those  already  demonstrated  to  be 
valuable  over  largo 
areas.  Those  men- 
tioned have  all  been 
tested  in  a  small  way. 
In  many  parts  of 
the  country  trees  with 
conspicuous  flowers 
and  those  with  edible 
fruits  or  nuts,  and 
even  horse-chestnuts, 
although  the  nuts  are 
not  edible,  are  badly 
mutilated  by  the  pub- 
lic. Every  effort 
should  be  made  to  cre- 
ate a  sentiment  that 
will  protect  these  at- 
tractive additions  to 
street  adornment,  but 
where  the  sentiment 
does  not  exist  it  is  bet- 
ter to  avoid  the  plant- 
ing of  SUch  trees  ex-  FIG.  I.— Narrow  upright  trees  (Lombardy  poplars)  on  a 


cept  in  a  limited  way. 


narrow  street.     Washington,  D.  C. ;  midsummer. 

Some  cities  have  ordinances  against  the  planting  of  certain  trees 
because  their  roots  sometimes  obstruct  sewers.  Among  these  trees 
are  the  Eucalyptus  and  some  of  the  poplars.  The  silver  maple  is  also 
bad  in  this  respect.  The  roots  of  any  tree  are  liable  to  find  their  way 
into  a  defective  sewrer,  but  the  trees  mentioned  are  especially  notice- 
able because  of  their  vigorous  root  growth.  It  may  be  questioned 
whether  a  tree  should  be  condemned  for  this  growth,  as  it  may  be 
better  to  have  a  defective  sewer  thus  revealed  than  to  continue  a 
menace  to  public  health. 

The  poplars  and  the  silver  maple  are  also  objectionable  because 
their  shallow  roots  often  interfere  with  pavements,  especially  poorly 


1208. 

constructed  ones.    Besides  the  native  trees  many  introduced  trees  have 
proved  valuable. 

TREES  FOR  DIFFERENT  REGIONS. 

To  simplify  the  consideration  of  the  kinds  of  street  trees  likely  to 
prove  satisfactory,  the  United  States  has  been  arbitrarily  divided 
into  the  regions  shown  in  figure  4,  an  endeavor  being  made  to  have 
each  division  represent  an  area  with  similar  growing  conditions. 
A  discussion  of  the  strong  and  weak  points  of  the  different  kinds  will 
be  found  with  the  descriptions  of  the  kinds  further  on  in  this  bulletin. 


FIG.  2. — Live  oaks,  the  handsomest  southern  street  tree  for  broad  streets.     Biloxi,  Miss. ; 

late  summer. 

Region  i. 

Region  1  comprises  the  mild  humid  portion  of  the  northern  Pacific  coast 
east  to  the  Cascade  Mountains,  including  the  western  third  of  Washington  and 
<>n-cron  and  a  portion  of  northern  California.  The  trees  native  to  western 
Europe  are  adapted  to  this  region,  as  the  climatic  conditions  are  quite  com- 
parable. Most  of  our  American  trees  also  succeed  here. 

Desirable  varieties  for  street  planting  in  region  1  are  the  Oregon,  Norway, 
sycamore,  and  sugar  maples ;  California  walnut ;  tulip ;  European  linden ;  bass- 
wood;  sycamore;  London  plane;  white  and  European  ashes;  English  and 
American  elms ;  English,  red,  and  pin  oaks ;  ginkgo ;  and  the  black  locust. 

Region  2. 

Region  2  is  that  portion  of  California  lying  between  the  Sacramento  and  San 
Joaquin  Valleys  and  the  Pacific  Ocean.  Many  varieties  of  trees  will  succeed 
here  if  given  water.  Because  of  the  lack  of  water,  unless  specially  irrigated, 
the  more  drought-resistant  species  should  be  used. 

Deciduous  trees  useful  for  this  region  are  the  London  plane;  the  California 
and  common  sycamore;  English,  Huntingdon,  and  American  elms;  Oregon, 


Trees  for  T'owh'dnd  'C<v 


Norway,  sycamore,  and  English  maples;  white,  green,  and  European  ashes;  red, 
English,  and  pin  oaks ;  European  linden ;  basswood ;  California  walnut ;  honey 
and  black  locusts ;  horse-chestnut ;  ^.Ibizzia ;  and  the  Japanese  varnish  tree,  or 
Sterculia. 

Evergreen  trees  which  will  succeed  in  region  2  are  the  Eucalyptus  in  variety, 
acacias,  rubber,  magnolia,  California  live  oak,  Victorian  and  poplar-leaved  bottle 
trees,  and  in  the  southern  portions  the  California  pepper,  silk  oak,  and  jaca- 
randu.  Palms  are  much  planted,  but  they  do  not  make  good  street  trees  except 
where  a  formal  effect  instead  of  shade  is  desired. 

Region  3. 

Region  3  comprises  the  Sacramento  and  San  Joaquin  Valleys. 

The  deciduous  trees  for  this  region  are  the  California  walnut ;  London  plane ; 
California  and  common  sycamores ;  Oregon,  Norway,  and  sycamore  maples ; 
white,  European,  and  green  ashes ;  red,  English,  valley,  and  pin  oaks ;  European 
linden ;  basswood  ;  Eng- 
1  ish  and  Huntingdon 
elms  ;  honey  locust ;  and 
horse-chestnut.  China- 
berries  and  Texas  um- 
brellas are  much  planted 
in  these  valleys,  but  are 
not  good  street  trees. 
Olives  and  palms  are 
suitable  only  for  formal 
effects.  Eucalypti  are 
satisfactory  but  are  liable 
to  make  trouble  with  de- 
fective sewers.  Acacias 
grow  especially  well  ex- 
cept in  the  extreme  north- 
ern part  of  this  region. 


Region  4. 


FIG.  3. — Formal  trees  in  a  central  parking,  but  appro- 
priate trees  wanting  on  the  sides  of  the  street.  Canary 
Island  date  palms  in  Merced,  Calif. ;  midsummer. 


Region  4  includes  the 
country  from  the  Sacra- 
mento and  San  Joaquin  Valleys  to  the  crest  of  the  Sierra  Nevada  Mountains. 
It  varies  in  elevation  and  correspondingly  in  temperature  and  the  amount  of 
available  moisture. 

Where  the  moisture  is  sufficient  the  deciduous  trees  recommended  for  region 
3,  except  the  valley  oak  and  possibly  the  California  sycamore,  may  be  used. 
Where  there  is  less  moisture,  the  thornless  honey  locust,  black  locust,  green  ash, 
hackberry,  poplars,  ash-leaved  maple,  and  the  American  elm  if  it  can  be 
watered  the  first  few  years  may  be  planted.  In  the  warmer  sections  the  china- 
berry  and  Texas  umbrella  may  be  used. 

Region  5. 

Region  5  comprises  the  hot  semiarid  country  of  southern  California  and 
southwestern  Arizona,  which  is  dependent  on  irrigation. 

The  best  deciduous  trees  for  this  region  are  those  suggested  for  the  drier 
portions  of  region  4.  With  ample  irrigation  the  deciduous  trees  recommended 
for  region  3  might  grow. 

Among  the  evergreens  the  Texas  palmetto,  Parkinsonia,  and  the  Washingtonia 
and  some  other  palms  can  be  used  where  other  trees  do  not  succeed.  The  red 


8 


1208. 


and  desert  gums  may  be  used  also  in  the  drier  regions.    With  ample  irrigation 
the  evergreens  suggested  for  region  2  should  succeed. 

Region  6. 

Region  6  is  the  intermountain  section,  extending  from  the  crest  of  the  Cascade 
and  Sierra  Nevada  Mountains  eastward  to  the  eastern  base  of  the  Rocky  Moun- 
tains. The  region  includes  great  variations  in  growing  conditions,  often  in  very 
short  distances.  As  a  whole  it  is  semiarid,  and  in  most  places  trees  can  hardly  be 
expected  to  thrive  without  irrigation,  although  in  some  of  the  mountain  valleys 
and  on  some  of  the  mountain  slopes  almost  ideal  conditions  for  tree  growth 
exist. 

In  the  drier  parts  of  the  region  only  those  deciduous  trees  that  are  weeds 
under  more  congenial  conditions  can  be  grown.  Those  that  can  be  planted  with 


FIG.  4. — Outline  map  of  the  United  States,  showing  the  regions  within  which  essentially 
similar  conditions  for  tree  growth  exist. 

the  greatest  hope  of  success  are  the  thornless  honey  locust,  black  locust,  green 
ash,  hackberry,  and  where  the  others  do  not  succeed,  the  poplars  and  ash- 
leaved  maple.  If  it  can  be  watered  for  a  few  years  the  American  elm  usually 
can  be  grown,  and  in  the  southern  half  of  the  region  the  Mississippi  hack- 
berry  will  probably  succeed.  Near  the  southern  border,  on  lower  elevations, 
the  chinaberry  and  Texas  umbrella  can  also  be  planted.  In  the  locations  most 
favored  naturally  or  where  irrigation  is  possible,  the  trees  suggested  for  region 
9  can  be  used. 

Evergreens  that  may  be  used  for  the  drier  portions  of  the  southern  part  of 
region  6  are  the  Parkinsonia  and  the  Texas  palmetto. 

Native  trees  should  be  sought  and  tried. 

Region  7. 

Region  7  is  the  northern  and  central  parts  of  the  Great  Plains  area  from  the 
foot  of  the  Rocky  Mountains  at  about  the  5,000-foot  contour  line  east  to  the 


Trees  for  Town  and  City  Streets.  9 

ninety -eighth  meridian.  It  is  rather  uniform  in  general  conditions,  the  character 
of  soil  having  no  wide  divergence  and  the  elevation  increasing  gradually  from 
south  to  north  and  from  east  to  west.  The  rainfall  gradually  increases  from 
west  to  east  until  at  about  the  ninety-eighth  meridian  the  conditions  are  more 
favorable  for  tree  growth. 

The  trees  to  be  relied  on  are  the  thornless  honey  locust,  common  hackberry, 
black  locust,  green  ash,  ash-leaved  maple,  the  poplars,  and  the  Chinese  elm. 
The  American  elm  and  the  silver  maple  will  frequently  prove  satisfactory  if 
they  can  be  watered  the  first  few  years  after  transplanting.  The  mossy-cup  oak 
is  another  tree  worth  testing  in  a  small  way,  as  it  is  native  a  little  east  of  the 
ninety-eighth  meridian.  The  bass  wood  and  Norway  maple  would  probably 
succeed  if  supplied  with  plenty  of  water. 

Region  8. 

Region  8  is  the  southern  part  of  the  Great  Plains. 

In  addition  to  the  deciduous  trees  recommended  for  the  northern  Great  Plains 
(region  7),  the  Mississippi  hackberry,  Texas  umbrella,  and  chinaberry  may  be 
successfully  grown. 

Evergreen  trees  that  may  be  used  in  region  8  are  the  Texas  palmetto  and 
Parkinsonia. 

Region  9. 

Region  9  is  the  upper  Mississippi  Valley,  including  the  area  eastward  from 
that  already  considered  to  Lake  Michigan  and  south  to  southern  Kansas.  It  is 
more  favorable  to  tree  growth  than  regions  6  and  7. 

Trees  which  will  succeed  here  are  the  American  elm ;  red,  pin,  mossy-cup,  and 
other  native  oaks;  white  ash;  sycamore;  basswood;  and  Norway  and  sugar 

maples. 

Region  10. 

Region  10  includes  the  northeastern  part  of  the  country  from  eastern  Illinois 
to  the  Atlantic  Ocean,  and  extends  southward  through  the  Appalachian  Moun- 
tains. It  is  most  favorable  for  tree  growth. 

The  best  trees  for  street  planting  in  region  10  are  the  red  and  pin  oaks,  Lon- 
don plane,  sycamore,  the  staminate  form  of  the  ginkgo,  basswood,  tulip,  Nor- 
way maple,  white  ash,  thornless  honey  locust,  American  elm,  and  in  the  south- 
ern portion  of  the  region  on  light  land  the  sweet  gum.  The  red  and  sugar  maples 
are  among  the  best  trees  for  suburban  conditions.  The  hackberry  will  grow, 
but  should  be  discarded  in  favor  of  better  varieties.  The  mossy-cup  and  chestnut 
oaks  are  worthy  of  trial  on  gravelly  soils  in  the  suburbs. 

Region  n. 

Region  11  includes  the  lower  Mississippi  Valley  and  the  country  east  of  the 
southern  Appalachian  Mountains,  extending  from  the  light  lands  near  the  South 
Atlantic  and  Gulf  coasts  to  the  northern  limits  of  the  distinctively  southern 
flora. 

The  typical  street  trees  of  this  region  are  the  willow  oak  (fig.  5)  and  water 
oak,  the  former  a  valuable  street  tree,  the  latter  good  when  young  but  compara- 
tively short  lived,  with  no  advantages  over  the  willow  oak.  Other  good  trees 
are  the  red,  Spanish,  laurel,  Darlington,  and  pin  oaks,  tulip,  sweet  gum,  Ameri- 
can elm,  red  and  Norway  maples,  and  the  ginkgo. 

Region  12. 

Region  12  is  the  land  near  the  coast  from  Wilmington,  N.  C.,  to  the  Mexican 
border,  exclusive  of  the  southern  part  of  Florida. 
63943°— 22— Bull.  1208 2 


10 


1208. 


Good  deciduous  trees  for  this  region  are  the  willow,  laurel,  Darlington,  and 
Spanish  oaks,  tulip,  sweet  gum,  sycamore,  London  plane,  American  elm,  and 
the  staniinatr  form  of  the  ginkgo.  The  honey  locust,  red  or  scarlet  maple, 
Norway  nmph\  and  the  hackberries  are  not  so  good. 


FIG.  5. — Willow  oak  in  winter,  Washington,  D.  C.    One  of  the  best  street  trees  for  regions 

11  and  12. 

The  live  oak  is  the  characteristic  tree  of  region  12  (fig.  2)  and  is  the  pride  of 
the  cities  that  have  used  it.  Even  though  an  evergreen  it  is  an  excellent  street 
tree,  as  it  is  large,  spreading,  and  open.  The  palmetto  and  palms  thrive  and 
may  be  used  for  formal  effects.  The  evergreen  magnolia  is  a  good,  broad- 
leaved  evergreen.  The  laurel  oak  is  evergreen  in  the  southern  parts  of  this 
region. 


Trees  for  Town  and  City  Streets.  11 

Region   13. 

Region  13  consists  of  the  southern  part  of  Florida.  The  deciduous  trees 
suitable  for  this  section  are  the  willow,  Spanish,  and  southern  red  oaks;  Amer- 
ican elm ;  Mississippi  hackberry ;  and  in  the  southern  half  of  the  region  the 
Poinciana. 

Evergreen  trees  are  better  suited  to  region  13  than  to  any  other  portion  of 
the  United  States  except  possibly  southern  California.  Among  the  best  are 
the  live  and  laurel  oaks,  evergreen  magnolia,  camphor,  rubber,  silk  oak,  or 
grevillea,  and  casuarina. 

TREES  FOR  SPECIAL  PURPOSES. 

In  the  heart  of  a  city,  where  the  greatest  difficulty  is  experienced 
in  getting  trees  to  grow,  the  ailanthus  will  probably  thrive  when 
nearly  all  other  kinds  fail.  The  sycamore  and  the  London  plane 
are  also  good.  The  Carolina  poplar  will  frequently  grow  in  such 
places  and  its  use  may  sometimes  be  warranted. 

For  very  narrow  streets  the  Lombardy  poplar  is  the  best  tree. 
(See  fig.  1.)  For  use  within  the  reach  of  ocean  spray  or  on  sandy 
lands  near  the  coast,  the  red  oak  and  the  red  or  scarlet  maple  are 
suitable  as  far  south  as  Charleston,  S.  C.,  while  the  sweet  gum  and 
the  live  oak  are  equally  good  from  Norfolk  southward  and  along  the 
Gulf  of  Mexico.  The  red  oak,  sweet  gum.  #ed  maple,  and  eastern 
live  oak  are  all  grown  successfully  along  the  Pacific  Ocean,  while 
the  California  live  oak  can  be  used  from  San  Francisco  southward. 
The  trees  that  endure  the  most  alkali  appear  to  be  the  bladder-nut 
tree.  London  plane,  peppermint  gum  arid  its  variety  Eucalyptus 
amygdalina  angustifolia,  and  the  Washingtonia  and  other  hardy  fan 
palms,  Canary  Islands  date  palm,  the  camphor  tree,  and  Acacia 
cy clops  and  Acacia  retinodes.  Only  the  first  two  withstand  severe 
freezing  weather.  The  red  oak  and  the  red  maple  are  worth  test- 
ing for  alkali  conditions. 

DESCRIPTIONS  OF  STREET  TREES. 

ACACIA. 

The  acacias,  or  wattles,  are  a  large  group  mostly  of  small  trees 
with  showy  yellow  flowers.  Although  much  used  in  California, 
many  of  them  are  too  small  to  make  satisfactory  shade  trees,  and 
because  of  shallow  rooting  they  are  injurious  to  sidewalks.  They 
also  stump-sprout  badly.  They  thrive  in  regions  2  and  3  and  in 
restricted  portions  of  regions  1  and  5. 

The  Australian  blackwood,  blackwood  acacia,  or  wattle,  often 
also  called  black  wattle  (fig.  6),  is  a  strong,  upright  tree,  growing 
to  a  height  of  75  feet  and  forming  a  well-shaped  head.  It  is  badly 
affected  by  citrus  scale,  and  on  this  account  its  planting  is  some- 
times prohibited. 


12 


Farmers'  Bulletin  1208. 


The   black   wattle   is   a   strong-growing  round-headed   tree   that 
reaches  a  height  of  40  feet  and  has  dark-green  leaves. 


FIG.  6. — Blackwood  acacia,  often  called  black  wattle.   Bakersfleld,  Calif. 

The  green  wattle  is  a  rapid-growing  tree  that  grows  to  a  height 
of  60  feet  and  forms  a  round  head  with  finely  cut  leaves. 


Trees  for  Town  and  City  Streets. 


13 


The  silver  wattle  is  much  like  the  black  wattle  except  that  its 
leaves  and  young  branches  are  covered  with  a  whitish  down. 

AILANTHUS. 

The  ailanthus,  or  tree  of  heaven,  is  a  tall,  broad,  handsome  tree 
that  is  especially  valuable  in  the  heart  of  closely  built  or  smoky 
cities.  The  staminate  and  pistillate  flowers  are  borne  on  separate 
trees.  Only  the  pistillate  trees  should  be  used,  as  the  odor  of  the 
blossoms  of  the  staminate  ones  is  very  objectionable  for  about  10 
days  in  late  spring.  These  may  be  produced  by  grafting  from  pistil- 


FIG.  7.— White  ash  trees  on  a  street  in  Washington,  D.  C. 

late  trees  or  by  propagating  from  suckers  or  root  cuttings  from  such 
trees  if  they  have  not  been  grafted.  The  ailanthus  may  not  suc- 
ceed in  regions  5  and  13. 

ASH. 

Three  kinds  of  ash  trees  are  useful  for  street  planting. 

The  white  ash  (fig.  7)  is  a  large  oval-headed  tree,  reasonably  satis- 
factory on  rich  lands  in  regions  1,  2,  3,  4,  9,  10,  11,  and  12,  but  it  is 
better  adapted  to  suburban  than  to  urban  conditions. 

The  green  ash  is  one  of  the  few  successful  trees  in  regions  6,  7, 
and  8  and  may  succeed  in  region  5.  It  grows  well  throughout  the 
remainder  of  the  United  States,  but  is  of  less  value  than  other  trees 
there.  It  is  much  smaller  than  the  white  ash,  with  a  broad  round  top. 

The  European  ash  is  a  large,  handsome,  round-headed  tree  suited 
to  regions  1,  2,  3,  and  4, 


14 


Farmers'  Bulletin  1208. 

CAMPHOR. 


The  camphor  tree  (fig.  8)  is  a  large,  handsome,  oval-headed  ever- 
green that  will  succeed  in  the  southern  half  of  region  2,  in  regions 


Fn;.  8. — A  camphor  tree. 

3,  5,  and  13,  and  in  the  warmer  parts  of  region  12.  It  will  endure 
more  frost  than  the  orange,  and  where  it  is  successfully  grown  it  is 
deservedly  popular, 


Trees  for  Town  and  City  Streets. 


15 


CHINABERRY. 


The  chinaberry,  sometimes  known  as  the  China  tree,  is  a  small, 
round-headed,  short-lived  tree  that  will  grow  in  regions  2,  3,  5,  8, 
11,  12,  and  13  and  near  the  southern  edge  of  region  C.  It  is  too  short 
lived  to  be  considered  for  planting  where  other  trees  will  grow. 

The  umbrella  tree,  or  Texas  umbrella,  is  a  small,  compact  form  of 
the  chinaberry  with  an  umbrella-shaped  top.  It  is  useful  for  formal 
effects,  as  in  the  parking  on  a  wide  street  where  taller  trees  are  used 
on  the  side.  It  will  grow  in  regions  2,  3,  5,  8,  11,  12,  and  13  and  in 
the  southern  parts  of  region  G. 


FIG.  U. — American  eims  in  winter,  Washington,  D.  C. 
ELM. 

The  elms  are  large,  handsome  shade  trees  suitable  for  use  over  a 
wide  range  of  territory. 

The  American  elm,  sometimes  called  the  white  elm  and  water  elm, 
is  one  of  the  handsomest  American  shade  trees.  (Fig.  9.)  It  has 
been  the  standard  street  tree  of  New  England,  giving  to  the  roadsides 
and  village  streets  the  characteristic  appearance  which  is  so  attractive 
to  summer  visitors. 

The  American  elm  is  tall  and  spreading,  and  where  planted  as  near 
together  as  is  customary  on  streets  and  country  roads  the  effect  of 
the  mature  trees  is  that  of  an  arch  formed  by  the  growing  together 
of  their  spreading  tops.  It  is  of  rapid  growth  and  long  lived. 


16  Farmers'  Bulletin  1208. 

This  elm  drops  its  leaves  very  early  in  the  fall,  but  it  comes  into 
leaf  early  in  the  spring.  Because  of  its  manner  of  branching  it  is 
especially  liable  to  splitting  by  heavy  winds.  This  trouble  may  be 
lessened  by  selecting  specimens  with  a  close,  compact  habit  of  growth 
or  possibly  also  by  great  care  in  training  young  trees.  Two  limbs 
separating  from  one  another  by  a  very  small  angle,  that  is,  when 
they  start  to  grow  in  nearly  the  same  direction,  make  a  crotch  that 
may  split.  Where  two  limbs  separate  at  nearly  a  right  angle  or 
where  three  or  more  limbs  of  about  equal  size  grow  from  a  common 
point  or  very  nearly  so,  the  crotch  is  likely  to  be  much  stronger. 
Careful  pruning  and  training  to  provide  a  proper  system  of  branches 
may  be  especially  helpful  with  this  elm. 

Because  of  the  attacks  of  the  elm  leaf -beetle2  and  the  European 
elm  bark  louse,3  many  handsome  trees  have  been  severely  damaged 
or  killed  before  communities  were  properly  equipped  for  fighting 
them,  but  with  careful  spraying  these  insects  may  be  kept  in  check. 
On  account  of  the  existence  of  these  pests  and  because  they  are 
gradually  spreading  to  new  territory,  tree  planters  should  consider 
carefully  whether  it  is  advisable  to  plant  the  elm.  Where  there  is 
no  danger  from  these  insects,  it  is  one  of  the  best  of  street  trees. 
Consultation  with  the  nearest  State  agricultural  experiment  station 
or  with  the  Entomologist  of  the  United  States  Department  of  Agri- 
culture would  be  advisable  before  deciding  to  plant  it. 

The  best  specimens  are  to  be  found  in  the  northern  part  of  region 
10,  although  the  elm  is  being  grown  all  over  the  United  States  and 
is  proving  a  valuable  street  tree  even  in  towns  and  villages  of  re- 
gions where  the  rainfall  is  as  low  as  15  inches.  It  is  not  recom- 
mended for  planting  in  regions  3  and  5. 

The  English  elm  is  a  tall,  oval-headed,  compact,  handsome  tree 
(fig.  10)  with  leaves  smaller  than  the  American  elm  which  stay  on 
much  later  in  the  fall.  In  regions  1  and  2  it  is  at  its  best,  in  the 
former  equaling  the  American  elm  and  in  the  latter  excelling  it.  It 
also  thrives  in  regions  3  and  10  and  in  the  eastern  part  of  region  11. 

The  Huntingdon  elm  is  a  comparatively  round-headed  European 
variety.  It  is  a  large,  handsome  tree  with  good  foliage  and  is  more 
compact  than  the  American  elm.  It  succeeds  well  in  regions  1,  2, 
3,  and  4. 

The  wahoo,  or  winged  elm,  is  native  to  the  South  Atlantic  and 
Gulf  States  near  the  ocean.  It  has  larger  leaves  than  the  American 
elm  and  is  not  as  spreading  in  its  growth,  but  it  succeeds  well  on  city 
streets  in  regions  11,  12,  and  13. 

1  Galerucella  luteola  Mull.  (Data  regarding  insects  furnished  by  the  Bureau  of  Ento- 
mology. ) 

*  Oossypuria  spuria  Mod. 


Trees  for  Town  and  City  Streets. 

EUCALYPTUS. 


17 


Many  species  of  Eucalyptus  can  be  used  for  street  planting  in 
regions  2,  3,  and  5.     Some  cities  prohibit  their  planting  because  their 


FIG.  10. — An  English  elm,  San  Jose,  Calif. 

roots  may  penetrate  defective  sewers,  and  in  other  cities  they  must 
be  kept  at  least  TO  feet  from  a  sewer,  though  even  this  distance  may 
not  prove  permanently  effective. 
63943°— 22— Bull.  1208 3 


18  Farmers'  Bulletin  1208. 

A  few  eucalypti  arc  being  planted  in  southern  Florida,  but  on 
account  of  the  moist  climate  they  are  not  likely  to  succeed  except 
on  the  drier  grounds  of  the  interior,  and  even  there  they  are  not 
equal  to  the  many  excellent  species  that  thrive  there.  They  are  tall, 
handsome,  quick-growing  trees,  usually  bearing  two  kinds  of  leaves 
at  some  time  in  their  development. 

The  blue  gum  is  one  of  the  best  eucalypti  and  the  one  most  com- 
monly used  in  California.  It  is  tall,  globular  headed,  handsome,  and 
will  survive  several  degrees  of  frost,  but  it  will  not  withstand  the 
heat  of  the  deserts  in  region  5.  Its  roots  are  especially  likely  to 
invade  sewers. 

The  desert  gum  is  one  of  the  trees  most  resistant  to  heat  and  cold. 
and  it  makes  a  handsome  avenue  tree.  It  has  pendent  branches  that 
have  a  tendency  to  severe  splitting  with  age,  but  with  early  attention 
this  may  be  overcome  largely.  It  may  prove  especially  valuable  for 
region  5. 

The  manna  gum  is  another  Eucalyptus  which  withstands  several 
degrees  of  frost  and  makes  an  excellent  roadside  tree.  Some  forms 
shed  their  bark  in  long  bands  that  leave  the  trunks  almost  white. 
Many  people  consider  it  a  dirty  tree  on  this  account. 

The  red  gum  grows  with  a  broad  head,  is  one  of  the  most  resistant 
of  the  eucalypti  to  frost,  drought,  and  heat,  and  succeeds  wherevpr 
any  of  these  trees  can  be  grown  in  regions  2,  3,  or  5,  but  is  most 
useful  in  region  5. 

The  sugar  gum  is  a  drought-resistant  variety,  but  it  does  not 
withstand  cold.  It  is  a  common  roadside  tree  in  southern  California, 
but  becomes  straggling  with  age. 

GINKGO. 

The  ginkgo,  or  maidenhair  tree  (fig.  11,  B) ,  is  a  native  of  Japan  that 
thrives  in  a  cool  climate  or  a  hot,  moist  one  and  succeeds  in  regions 
1,  9,  10,  11,  12,  and  13.  It  is  extremely  erratic,  sometimes  grow- 
ing well,  sometimes  practically  not  growing  at  all,  but  wrhere  it 
succeeds  it  is  very  disease-resistant  and  it  withstands  severe  wind- 
storms remarkably  well.  The  leaf  is  peculiar  in  appearance,  re- 
sembling in  outline  a  much  enlarged  leaflet  of  maidenhair  fern  with 
a  corrugated  surface.  The  tree  is  conical  when  young,  but  as  it 
reaches  maturity  its  top  usually  fills  out,  making  a  broad,  almost 
flat-topped,  handsome  tree.  Only  the  staminate  form  should  be 
used,  because  the  pistillate  form  bears  fruits  the  flesh  of  which  is 
slippery  and  dangerous  when  it  drops  to  the  pavement,  and  to 
some  people  it  is  somewhat  poisonous  to  the  touch.  Ginkgo  trees, 
therefore,  would  need  to  be  propagated  by  budding  or  grafting  from 
the  staminate  form. 


Trees  for  Town  and  City  Streets. 


19 


HACKBERRY. 

The  hackberry,  or  sugarberry,  is  especially  valuable  in  regions 
6,  7,  8,  and  9,  as  it  grows  satisfactorily  with  comparatively  slight 


FIG.  11. — Trees  18  years  old  on  adjacent  streets  :  A,  Pin  oaks ;  B,  ginkgos ; 
C,  Norway  maples. 

rainfall.    It  is  also  much  used  in  region  11,  but  should  be  superseded 
there  by  other  varieties.     It  is  of  moderate  size,  with  an  oblong 


Farmers'  Bulletin  i20S. 


head  of  rather  open  growth  and  leaves  much  like  those  of  the  elm. 
It  is  comparatively  short  lived. 

The  name  sugarberry  comes  from  the  sweet  black  berries  that  are 
borne  in  the  early  fall.  The  tree  is  sometimes  affected  by  a  fungous 
trouble  known  as  witches'-broom,  that  causes  large  numbers  of  small 
sprouts  to  start  from  the  affected  portion  and  gives  the  infected  tree 
an  unsightly  appearance.  The  hackberry  should  not  be  planted 
where  this  trouble  is  prevalent. 

The  Mississippi  hackberry,  more  often  called  sugarberry  than 
the  common  hackberry,  is  a  large,  open,  oblong-headed  tree 
with  smoother  leaves  than  the  common  hackberry.  It  is  useful  in 


> 


• 


FIG.   12. — A  street  planted  with  honey  locusts  ;  l:it 


.  Washington,  1>.  c 


the  southern  part  of  region  6,  in  region  8,  and  to  some  extent  in 
regions  11  and  12.  It  thrives  well  under  the  same  adverse  moisture 
conditions  as  the  common  hackberry.  The  trunk  and  the  large 
branches  have  little  wartlike  projections  of  the  bark  scattered  irregu- 
larly over  them.  The  small  twigs  are  sometimes  more  or  less  spotted 
or  winged  in  the  same  way.  The  tree  is  rather  larger  than  the 
common  hackberry  and  apparently  is  less  subject  to  witches'-broom. 

HONEY  LOCUST. 

The  honey  locust  is  a  large,  open,  round-headed,  fine-foliaged  tree, 
admitting  much  light  through  its  top.  (Fig.  12.)  The  common 
form  has  .stiff  spines  2  to  6  inches  long,  or  even  longer,  but  there  is 
also  a  form  without  spines,  which  is  the  one  that  should  be  used  for 


Trees  for  Town  and  City  Streets. 


21 


street  planting.  It  is  a  useful  tree  in  regions  1,  2,  3,  9,  10,  and  11,  but 
is  especially  valuable  for  planting  in  regions  6,  7,  and  8,  and  may 
prove  useful  in  region  5. 

HORSE-CHESTNUT. 

The  horse-chestnut  has  very  showy  blossoms,  and  when  in  bloom 
an  avenue  of  these  trees  commands  attention.  It  is,  however,  likely 
to  be  broken  by  boys  clubbing  it  for  its  inedible  nuts.  It  is  a 
medium-sized  round-headed  tree  that  does  much  better  under  sub- 
urban conditions  than  in  a  city.  It  thrives  in  regions  1,  2,  3,  and  10, 
but  in  some  places  its  leaves  are  affected  by  a  midsummer  blight 


mm 

ii 

i  \  ;*-  •• 


FIG.  13. — Basswoods  in  winter,  Washinglon,  D.  C. 

which  makes  it  unsightly  during  the  remainder  of  the  season.  It 
is  a  close  relative  of  the  Ohio  buckeye,  which  is  also  a  handsome 
though  less  desirable  tree. 

LINDEN. 

The  basswood,  or  linden  (fig.  13),  is  a  large  round-headed  tree  that 
is  excellent  for  roadsides  in  surburban  locations  and  does  well  on  city 
streets  if  the  conditions  are  not  too  severe.  On  account  of  the  dark 
upper  surface  and  the  lighter  under  surface  of  the  leaves  and- the 
sweet-scented  blossoms  in  early  summer  it  is  much  admired.  It  is 
not  as  reliable  as  some  of  the  other  shade  trees,  as  when  young  it  is 
sometimes  attacked  at  the  base  of  the  trunk  by  a  fungous  growth 
that  kills  the  tree.  When  once  established,  it  forms  handsome  avenues. 
It  is  suited  to  regions  1,  2,  3,  4,  7,  9, 10,  and  11. 
63943— 22— Bull.  1208 4 


22  Farmers'  Bulletin  1208. 

The  linden,  or  European  linden,  has  much  smaller  leaves  than  the 
American  linden  or  basswood,  with  more  contrast  between  their 
tipper  and  lower  surfaces.  It  is  about  the  same  size,  but  is  a  little 
more  compact  in  growth  and  holds  its  leaves  longer  in  the  fall.  It  is 
a  useful  tree  for  street  planting  in  regions  1,  2,  3,  4,  9,  10,  and  11. 

LOCUST. 

The  locust,  or  black  locust,  is  a  desirable  street  tree  in  regions  6,  7, 
and  S,  and  probably  in  region  5,  as  it  thrives  with  comparatively  little 
moisture.  It  makes  a  moderate-sized  oval  head  that  bears  sweet- 
scented  white  flowers  in  late  spring  or  early  summer.  Its  greatest 
drawback  is  its  liability  to  serious  injury  and  disfigurement  by  the 
locust  borer,4  but  with  proper  care  this  injury  can  be  prevented.5  In 
some  parts  of  the  East  it  is  also  subject  to  a  leaf  miner0  that  gives 
its  foliage  a  burned  appearance.  In  region  3  it  holds  its  seed  pods 
for  several  years,  and  thus  becomes  very  unsightly. 

MAGNOLIA. 

The  evergreen  magnolia  is  one  of  the  few  good  evergreen  trees 
(fig.  14)  for  street  planting,  but  it  is  adapted  only  to  regions  1,  2,  3, 
11,  12,  and  13.  There  are  but  few  conditions  that  warrant  the  plant- 
ing of  a  tree  having  foliage  as  thick  as  this  because  of  the  dense 
shade,  which  is  especially  undesirable  in  winter.  It  grows  to  be  a 
large  oval-headed  tree  and  bears  beautiful  large  white  blossoms  in 
late  spring  or  early  summer. 

MAPLE. 

Among  the  maples  are  some  undesirable  trees  much  used  for  street 
planting  and  some  that  are  valuable  only  in  restricted  areas  or  under 
special  conditions.  The  maples  are  not  as  satisfactory  for  street 
planting  as  usually  has  been  supposed,  few  of  the  species  being  suit- 
able for  this  purpose  and  these  only  in  a  limited  way. 

The  ash-leaved  maple,  or  box  elder,  is  native  to  all  of  the  country 
east  of  the  Rocky  Mountains  except  the  regions  near  the  South 
Atlantic  and  Gulf  coasts.  It  is  a  small,  quick-growing  tree  that  will 
thrive  almost  anywhere,  but  it  reaches  maturity  early.  There  m:i\ 
be  conditions  requiring  the  use  of  this  tree  in  regions  6,  7,  and  8,  but 
because  of  its  early  decay  and  of  its  being  subject  to  destruction  by 
wind  it  should  be  grown  only  when  the  other  trees  suggested  for 
these  regions  will  not  succeed. 

The  English  maple  is  small,  round  headed,  with  small  dark-green 
leaves,  useful  in  regions  1,  2,  3,  and  4. 

*  Cylene  roltiniae  Forst. 

6  Soc  I".  S.  Dept.  of  Agriculture  r.ullctin  7X7,  entitled  "  J'rotertion  from  UK*  Locust 
Borer." 

dorsalis  Thunb. 


Trees  for  Town  and  City  Streets. 


23 


The  Norway  maple  is  round  headed  and  eventually  reaches  large 
size,  but,  as  compared  with  most  of  the  other  maples,  it  is  slow  grow- 
ing (fig.  11,  C).  The  persistence  of  its  tendency  to  form  a  low  head 
makes  it  difficult  to  give  it  a  high  head  of  desirable  shape  (fig.  15). 


FIG.  14. — Magnolia,  or  evergreen  magnolia.     A  good  street  tree  where  an  evergreen 

is  permissible. 

It  is  also  very  thickly  branched,  and  its  foliage,  being  heavy  and  dark 
green,  permits  little  light  to  pass  through.  On  this  account  it  is 
rather  undesirable  for  street  planting.  By  severe  pruning  of  the 
interior  of  the  head  this  defect  may  be  somewhat  overcome.  The 
tree  is  practically  free  from  disease  and  insects,  with  the  exception  of 


24 


Farmers'  Bulletin  1208. 


a  leaf  aphis,7  which  produces  yellow  spots  on  the  leaves  and  causes 
them  to  drop  prematurely;  also,  the  honey  dew  which  they  produce 
is  so  abundant  at  times  as  to  cover  the  leaves  and  wet  the  sidewalk 
beneath  the  tree,  the  leaves  under  certain  weather  conditions  becom- 
ing blackened  with  dust  accumulating  and  a  fungus  growing  in  the 
secretion,  thereby  giving  the  tree  an  unsightly  appearance.  This 
aphis,  however.  i.s  not  always  present  and  does  not  seriously  injure 
the  tree.  The  Xorway  maple  comes  into  leaf  later  than  most  of  the 

other  maples,  but 
holds  its  leaves  later 
in  the  fall.  They 
usually  assume  a 
bright  yellow  hue  be- 
fore they  drop.  The 
leaves  are  preceded  by 
an  abundance  of  yel- 
low -  green  blossoms. 
On  account  of  its 
dense  shade  and 
masses  of  fine  fibrous 
roots  it  is  difficult  to 
grow  grass  under  this 
tree.  Its  good  shape 
and  attractive  dark- 
green  foliage  make  it 
popular  for  street 
planting  in  spite  of 
its  dense,  low  head. 
It  will  succeed  in  re- 
gions 1,  2,  3,  4,  9,  10, 
11,  and  12. 

The  Oregon  maple, 
also  known  on  the 
its  poor  Pacific  coast  as  broad- 
leaved  maple,  is  the 
large-leaved  maple  of  the  northern  Pacific  slope.  It  forms  a  large 
round  head,  and  with  its  unusually  large  dark-green  leaves  makes  a 
very  attractive  street  tree  that  succeeds  well  in  regions  1,  2,  3,  and  4. 
It  is  valuable  and  worthy  of  more  extended  cultivation  on  the  Pacific 
coast. 

The  red  maple,  scarlet  maple,  or  swamp  maple  is  one  of  the 
most  widety  distributed  American  trees.  It  is  found  from  Canada 
to  the  Gulf  of  Mexico  and  west  to  the  Rocky  Mountains.  Its  leaves 
are  the  smallest  of  the  eastern  native  maples,  but  it  grows  large  and 


FIG.  15. — A  Norway  maple  In  lato  wintor,  showin 
shape  when  trimmed  to  a  high  head. 


Trees  /or  Town  and  City  Streets. 


is  usually  of  rather  upright  outline.  It  is  better  adapted  to  suburban 
conditions  than  to  city  streets  and  is  one  of  the  few  trees  that  suc- 
ceed well  near  the  ocean.  It  has  bright-red  blossoms  before  the 
leaves  appear.  The  young  leaves  and  fruits  are  also  red.  The 
mature  leaves  begin  to  color  early,  some  branches  coloring  as  early 
as  the  middle  of  July,  assuming  brilliant  reds  and  yellows  and  stay- 
ing on  later  than  those  of  the  sugar  maple.  It  is  a  handsome  tree 
that  is  not  as  much 
used  as  it  deserves  to 
be  in  regions  1,  9,  10,' 
11,  12,  and  13. 

The  silver  maple, 
also  called  the  soft 
maple,  white  maple, 
and  swamp  maple,  is 
probably  more  used 
for  street  planting 
through  the  whole 
United  States  than 
any  other  tree,  though 
it  is  one  of  the  least 
desirable.  It  is 
usually  planted  be- 
cause it  is  a  quick- 
growing  tree,  but  it 
is  not  more  rapid  in 
growth  than  several 
other  trees  that  are 
much  better.  There 
are  three  serious  ob- 
jections to  its  use  as 
a  street  tree.  The 
first  is  its  brittle 
wood,  which  at  an 
early  age  is  easily  broken  by  ordinary  windstorms  and  causes  it  when 
a  comparatively  young  tree  to  become  unsightly.  The  second  is  its 
shallow  rooting,  which  has  a  tendency  to  destroy  pavements  and  also 
makes  it  difficult  to  grow  grass  near  the  trees.  The  roots  also  will 
grow  into  sewers.  The  third  is  its  tendency  to  decay;  the  tips  of 
the  limbs  frequently  die,  leaving  the  whole  top  of  the  tree  bare  of 
leaves,  and  the  wood  decays  quickly,  especially  if  the  bark  is  broken. 
For  this  reason  it  does  not  stand  pruning  as  well  as  most  other 
street  tre'es,  and  it  probably  has  been  pruned  more  ruthlessly  than 
any  other,  unless  it  is  the  Carolina  poplar.  It  should  never  be 
severely  deheaded  or,  as  it  is  popularly  called,  "  dehorned"  (fig.  16), 


FIG.  16. — Silver  maples  severely  headed  back,  an  improper 
way  to  treat  trees,  especially  silver  maples,  except 
under  very  unusual  conditions.  Washington.  D.  C. ; 
midsummer. 


26 


Farmers'  Bulletin  120$. 


as  the  stubs  will  practically  never  heal  over,  and  from  these  cuts 
decay  will  start,  which  in  a  very  few  years  will  rot  the  center  of  the 
limbs  and  trunk  and  thus  destroy  the  tree.  Although  it  forms  a 
large  round  head  with  an  open  top  and  its  foliage  is  pale  green 
above  and  almost  white  beneath,  making  a  very  delightful  shade,  it 
should  not  be  used  for  street  planting  where  other  trees  can  be  made 

to  grow.    Its  use  may 

be    warranted,    h  o  w  - 
ever,  in  region  7. 

The  sugar  maple,  or 
hard  maple  (fig.  17), 
is  especially  adapted 
to  gravelly  soils  in  re- 
gions 1,  10,  and  11,  the 
northern  parts  of  re- 
gions 2  and  3,  and  the 
eastern  and  southern 
parts  of  region  9.  It 
is  oval  headed,  large, 
and  handsome.  The 
leaves  come  early,  but 
in  late  summer  they 
begin  to  turn  brilliant 
yellow  and  red  and 
drop  before  most  other 
leaves.  The  sugar 
maple  does  not  thrive 
under  city  conditions, 
but  it  is  admirably 
adapted  to  suburban 
streets. 

Although  the  sycamore  maple  is  similar  in  appearance  to  the 
Norway  maple,  it  is  not  a  satisfactory  street  tree  in  the  eastern 
United  States.  It  succeeds,  however,  in  regions  1,  2,  3,  and  4. 

OAK. 

Of  the  trees  used  for  street  planting  the  oaks  are  best.  They 
probably  have  not  been  more  widely  planted  because  of  the  preva- 
lent belief  that  they  are  slow  growers  and  because  in  the  North  they 
are  rather  difficult  to  transplant.  Although  some  of  the  handsomest 
species,  like  the  white  oak  and  live  oak,  are  slow  growers,  those 
suitable  for  street  planting  are  comparatively  rapid  growing.  The 
white  oak  and  sugar  maple  shown  in  figure  17  are  each  32  years  old 
and  although  differing  in  shape  are  practically  the  same  size,  yet  the 
sugar  maple  has  been  considered  a  sufficiently  rapid  growing  tree 
to  be  planted  frequently  as  a  street  tree,  while  the  white  oak  has 


4-4 


FIG.  17.— A  sugar  maple  (on  the  loft)  and  a  white  oak 
(on  the  right),  each  32  years  old  and  nearly  the  same 
siza 


Trees  for  Town  and  City  Streets. 


27 


seldom  been  so  used,  probably  because  of  an  erroneous  impression 
that  it  is  of  too  slow  growth.  The  oaks  are  hardy,  most  of  them 
are  long  lived,  and  for  the  most  part  they  are  free  from  disease  and 
insect  attacks.  Some  of  the  southern  species  are  subject  to  attacks 
of  mistletoe. 

The  California  live  oak  is  an  evergreen  suitable  for  use  in  region  2 
and  succeeds  adjacent  to  the  ocean.  It  is  also  useful  in  region  3 
and  in  the  western  part  of  region  5.  It  is  easily  transplanted  when 
young,  especially  when  planted  from  pots. 


FIG.  18. — A  Darlington  oak  in  winter,  Darlington,  S.  C. 

The  chestnut  oak  is  a  native  of  gravelly  soils  on  eastern  moun- 
tains and  is  suitable  for  similar  soils  in  suburban  locations  in  regions 
9, 10,  and  11.  It  is  a  large,  handsome  tree. 

The  Darlington  oak  (fig.  18)  is  a  form  of  laurel  oak  especially 
desirable  for  street  planting.  It  is  large,  round  headed;  the  leaves 
are  a  trifle  narrower  and  not  quite  so  nearly  evergreen  as  the  laurel 
oak.  It  is  found  wild  about  Darlington,  S.  C.,  where  a  good  form 
of  the  laurel  oak  appears  to  have  been  introduced  as  a  shade  tree  in 
the  early  part  of  the  nineteenth  century.  Its  range  of  usefulness 
lies  in  regions  11  and  12. 

The  laurel  oak  is  a  large  oval-headed  tree  that  is  not  as  rugged 
and  irregular  as  the  live  oak,  but  is  suitable  for  street  planting  in 


28  Farmers'  Bulletin  1208. 

regions  11,  12,  and  13.  It  has  large,  thick,  glossy  leaves,  and  in 
the  warmer  regions  it  is  almost  evergreen.  It  is  readily  trans- 
planted, but  as  it  is  not  so  common  in  the  woods  as  the  willow  oak 
and  the  water  oak  it  has  not  been  so  much  used  as  a  street  tree. 

The  live  oak  (fig.  2)  is  probably  the  noblest  and  most  majestic 
of  the  oaks  of  regions  12  and  13.  It  is  evergreen  and  of  slow  growth, 
but  wherever  it  is  found,  whether  on  streets  or  in  public  parks,  it  is 
the  pride  of  the  people.  Although  an  evergreen,  it  is  sufficiently 
open  headed  to  make  a  good  street  tree.  When  it  becomes  old  it  is 
spreading,  and  as  a  rule  does  not  form  as  high  a  head  as  the  willow 
oak  and  the  laurel  oak.  Compared  with  other  southern  oaks  it  is 
difficult  to  transplant.  It  is  of  sufficient  merit  to  be  used  on  broad 
streets,  and  especially  on  boulevards,  where  the  good  of  the  future 
as  well  as  the  present  is  considered. 

The  mossy-cup  oak  or  bur  oak  is  native  in  the  northeastern 
part  of  the  United  States  and  west  of  the  Mississippi  River  on  the 
hills  lying  between  the  river  bottoms  and  the  prairies  west  to  the 
western  parts  of  the  Dakotas  and  Nebraska  and  central  Kansas  and 
Texas.  It  is  a  large,  handsome  tree  that  should  prove  satisfactory 
under  suburban  conditions  in  regions  7,  8,  9,  10,  and  11  and  on 
fertile  well-watered  soils. 

The  pin  oak  (fig.  11,  A),  sometimes  called  the  swamp  oak,  is  a  tall 
tree,  conical  when  youn<r,  oval  at  maturity,  with  a  drooping  habit  of 
the  lower  branches.  The  leaves  are  quite  finely  divided  and  of  a 
bright  glossy  green.  The  tree  comes  into  leaf  late  in  the  spring  and 
holds  its  foliage  late  in  the  fall.  On  many  specimens  the  dead  leaves 
hang  on  through  the  winter,  which  is  often  objectionable.  It  is 
adapted  to  narrower  streets  than  the  red  oak,  as  its  habit  of  growth  is 
not  so  spreading.  On  account  of  the  tendency  of  the  limbs  to  droop, 
particularly  as  they  get  older>  it  is  desirable  that  a  good  strong  leader 
should  be  developed,  so  that  the  lower  limbs  may  be  removed  from 
time  to  time  as  conditions  require.  The  pin  oak  thrives  on  wet  and 
on  heavy  clay  soils,  as  well  as  on  a  wide  range  of  other  soils.  Figure 
11  shows  pin  oaks,  Norway  maples,  and  ginkgos  18  years  old  on 
adjacent  streets,  and  illustrates  the  rapid  growth  of  this  oak.  At 
the  time  of  planting  these  trees  the  pin  oaks  were  thought  to  have 
the  poorest  location.  This  tree  is  adapted  to  regions  1,  2,  3,  4,  9, 
10.  and  11. 

The  red  oak  (fig.  19)  is  probably  the  best  tree  for  street  planting 
in  regions  1,  9, 10,  and  11  and  is  satisfactory  in  regions  6,  7,  8,  and  12. 
It  is  a  large,  oval,  open-headed  tree  of  rapid  growth.  Under  good 
conditions  a  young  red  oak  will  grow  4  feet  in  a  single  season.  Like 
the  other  oaks  it  is  slow  in  coming  into  leaf  in  the  spring,  but  holds 
its  foliage  late  in  the  fall.  The  leaves  usually  turn  a  brilliant  red 
before  they  drop.  It  is  comparatively  free  from  insect  and  fungous 
attacks,  and  it  is  one  of  the  few  trees  really  suitable  for  planting  close 


Trees  for  Towii'diid"Glfij  Streets.'"'1 


29 


to  the  ocean,  as  it  thrives  on  sandy  lands  only  a  few  feet  above  high 
tide  or  within  the  reach  of  ocean  spray. 

The  scarlet  oak  is  a  large,  open,,  round-headed  tree.  Its  leaves 
are  more  deeply  divided  than  those  of  the  red  oak.  The  leaves  turn 
a  brilliant  scarlet  in  autumn,  being  even  more  gorgeous  than  those  of 
the  red  oak.  This  tree  is  adapted  for  street  planting  and  is  especially 
desirable  for  suburban  conditions  in  regions  1,  9,  and  10. 

The  swamp  Spanish  oak  is  adapted  to  regions  11,  12,  and  13.  It 
belongs  to  the  red-oak  group,  but  is  larger  than  the  other  oaks  sug- 
gested for  street  planting.  It  is  well  adapted  to  suburban  locations, 
but  apparently  it  has  not  been  tested  under  severe  city  conditions. 


FIG.  19. — A  street  shaded  with  red  oaks  in  midsummer,  Washington,  D.  C. 

The  valley  oak  is  a  beautiful  tree  for  regions  2  and  3  and  the  more 
favorable  parts  of  region  5.  When  transplanted  young,  especially 
if  taken  from  a  pot,  it  is  easily  established  where  there  is  opportunity 
to  water  it  for  a  few  years. 

The  water  oak  is  frequently  confused  with  the  willow  oak  and 
the  laurel  oak,  as  these  three  oaks  are  not  distinguished  from  one 
another  except  by  close  observers  of  trees.  It  is  probably  more  used 
than  any  other  tree  in  the  cities  of  region  12  and  the  adjoining  por- 
tions of  region  11.  It  is  the  weed  of  the  southern  oaks  and  one  of  the 
weeds  of  the  street  trees  of  the  Southern  States.  It  is  comparatively 
short  lived  and  seems  to  be  more  subject  to  attacks  of  mistletoe  and 
more  easily  affected  by  windstorms  than  the  willow  oak,  the  Darling- 
ton oak,  and  the  laurel  oak.  This  tree  should  not  be  planted,  because 
it  is  less  desirable  than  the  other  oaks  mentioned. 

The  willow  oak  (see  fig.  5),  sometimes  erroneously  called  the  water 
oak,  is  one  of  the  best  of  the  quick-growing  oaks  for  use  in  regions 


•      ••      •»••      »,»•••         •       •       *  *  \ 

30  "''Tattle  ft*' 'Bulletin   1208. 


FIG.  20.— Leaves  of  some  of  the  southern  oaks  :  A,  Live  oak  ;  B,  willow  oak  ;  (7,  laurel  oak 

and  D,  water  oak. 


Trees  for  Town  and'^City' Afreets."  31 

11  and  12.  It  is  frequently  used  with  the  water  oak  for  street  plant- 
ing and  is  usually  confused  with  it.  It  is,  however,  a  distinct  tree, 
which  can  be  distinguished  readily  from  the  water  oak.  It  is 
longer  lived  and  is  its  equal  in  every  other  respect.  Trees  of  this 
variety  which  apparently  have  been  planted  about  80  years  are 
found  in  excellent  condition,  while  water  oaks  planted  at  the  same 
time  have  either  entirely  disappeared  or  are  showing  marked  evi- 
dences of  decline.  Figure  20  shows  the  characteristic  appearance 
of  the  leaves  of  these  nearly  related  species  of  oaks.  In  the  South 
the  willow  oak  is  readily  transplanted,  as  trees  12  feet  high  are 
dug  from  the  woods  and  planted  on  the  street  with  success  (fig.  21). 


FIG.  21. — Willow  oaks,  transplanted  from  the  woods,  as  they  appeared  near  the  eud  of 
the  second  summer.    Montgomery,  Ala. 

In  the  extreme  South  this  tree  is  nearly  half  evergreen.    Its  foliage 
does  not  assume  the  bright  colors  of  the  trees  of  the  red-oak  class. 

PALM.8 

Several  varieties  of  palms  are  used  more  or  less  for  street  planting 
in  regions  2,  3,  5,  12,  and  13.  Though  sometimes  effective  as  a 
formal  street  decoration  (fig.  22),  they  can  hardly  be  considered 
shade  trees. 

PALMETTO. 

Palmettos,  or  sabals,  abound  in  region  12  near  the  coast ;  succeed  in 
regions  3,  5,  and  13;  live  in  region  2;  but  are  seldom  grown  satis- 

8  The  palms  are  treated  on  the  basis  of  notes  furnished  by  Dr.  O,  F.  Cook,  of  the 
Bureau  of  Plant  Industry. 


32 


1208. 


factorily  close  to  the  Pacific  coast.  They  can  be  used  effectively 
for  formal  plantings  along  some  streets,  park  drives,  or  in  liberal 
central  parking  spaces  in  boulevards,  but  they  are  not  useful  as  a 
substitute  for  shade  trees.  Their  leaves  and  damaged  roots  should 
be  cut  off  in  transplanting,  and  they  should  be  set  about  3  feet  deep 
in  their  new  location. 

The  Carolina  palmetto  is  a  native  of  and  useful  in  regions  12  and 
13,  where  it  sometimes  attains  a  height  of  60  or  80  feet.  It  will 
thrive  in  regions  3  and  5,  but  is  used  less  there. 

The  Texas  palmetto  is  especially  valuable  for  southern  Texas, 
where  it  is  indigenous,  and  it  is  likely  to  succeed  generally  in  regions 


FIG.   22.— A   formal  planting  on   a   city  street.      Palms   with   interplantings. 

Calif.,  in  midsummer. 


Redlands, 


3,  5,  and  12.  It  grows  to  a  height  of  40  feet  and  in  appearance  is 
quite  distinct  from  the  Carolina  palmetto,  the  leaf  segments  being 
much  broader  and  less  drooping. 

The  Victoria  palmetto 9  is  another  hardy  species,  probably  a  native 
of  Mexico,  but  grown  for  many  years  at  Victoria,  Tex.  It  is  similar 
to  the  native  Texas  species  and  worthy  of  general  planting  in  the 
same  region.  A  feature  of  this  species  is  that  the  persistent  leaf 
bases  remain  alive  and  green  for  many  years  instead  of  turning 
yellow  or  brown,  as  in  the  Carolina  palmetto. 

WASHINGTONIA   PALM. 

Washingtonia  palms  are  a  very  conspicuous  feature  of  street  and 
ornamental  planting  in  southern  California.  Two  species  are  rep re- 


v  Cook,  O.  F.     A  new  ornamental  palmetto  in  southern  Texas.     In  U.   S.  Dept,  Agr., 
Bur.  Plant  Indus.  Cir.  113,  p.  11-14.     1913. 


Trees  for  Town  and  City  Streets.  33 

sented,  Washingtonia  filifera  Wendland  and  W.  robusta  Wendland. 
The  first  is  a  native  of  the  canyons  and  barren  slopes  that  surround 
the  Coachella  Valley  of  southern  California,  while  the  other  species 
probably  was  brought  in  the  early  days  of  travel  by  way  of  the 
Isthmus  of  Panama  from  the  region  of  San  Jose  del  Cabo,  the  ex- 
tremity of  Lower  California.  The  name  robusta  is  used  because 
this  species  grows  much  more  rapidly  in  height  than  W.  filifera, 
though  the  trunk  is  more  slender.  Both  species  are  hardy  and  thrive 
well  through  regions  2,  3,  and  5,  and  also  in  regions  12  and  13. 
Washing  tonics  robusta  requires  less  heat  than  W.  filifera,  but  both 
will  endure  several  degrees  of  frost.  Even  in  California  Washing- 
tonia  robusta  is  distinctly  preferable  for  localities  near  the  coast. 
In  the  vicinity  of  San  Diego  the  leaves  of  Washingtonia  filifera  be- 
come badly  infested  with  a  parasitic  fungus  that  does  not  attack 
Washingtonia  robusta. 

OTHER  HARDY  FAN  PALMS. 

The  species  most  commonly  used  for  street  and  ornamental  plant- 
ing in  the  California  coast  districts  is  the  Chinese  or  windmill  palm. 
This  palm  has  a  slender  trunk  clothed  with  brown  fibers,  flat  fan- 
shaped  leaves,  and  rather  straight  radiating  segments.  The  same 
species  is  hardy  at  New  Orleans  and  Charleston,  and  even  at  Laurens, 
S.  C.,  at  an  altitude  of  600  feet,  but  it  does  not  thrive  in  the  sandy 
soil  of  Florida. 

The  vegetable-hair  palm,  a  native  of  Spain,  Sicily,  and  North 
Africa,  is  similar  to  the  Chinese  palm  but  smaller  and  more  compact 
and  with  large,  sharp  spines  on  the  petioles  of  the  leaves.  When 
young  it  suckers  from  the  base,  like  the  date  palm,  so  that  clusters  of 
it  may  be  formed. 

The  Guadalupe  Island  palm  is  one  of  the  most  popular  species 
in  southern  California  in  the  region  of  Santa  Barbara,  Los  Angeles, 
and  San  Diego.  This  palm  is  a  nafive  of  Guadalupe  Island,  off 
the  coast  of  Lower  California,  and  is  not  known  to  occur  elsewhere  in 
the  wild  state.  It  is  well  adapted  to  the  cool  coast  climate  of  Cali- 
fornia, but  not  to  the  interior  valleys.  It  is  smaller  than  the  Wash- 
ingtonia palms,  with  a  rather  short  trunk,  15  to  20  feet  high,  and  a 
dense  crown  of  fresh  green  leaves. 

The  California  blue  palm,  formerly  placed  in  the  same  genus  with 
the  Guadalupe  Island  species,  is  very  distinct  in  habits  as  well  as  in 
general  appearance,  having  bluish  or  grayish  green  leaves,  strongly 
toothed  petioles,  and  long,  slender  flower  clusters.  The  trunk  is 
very  robust,  often  2  to  3  feet  in  diameter,  and  attains  a  height  of  30 
to  40  feet.  Several  of  these  features  are  shared  with  the  Washing- 
tonia palms.  It  also  has  the  ability  to  grow  in  the  dry,  hot  interior 


34  *''•;  --'.  yFarfntFs  :BtiUetin  120$. 

valleys    (regions  3  and  5).     In  Texas  the  blue  palm  has  proved 
hardy  at  San  Antonio,  and  even  as  far  north  as  Austin. 

DATE  PALM. 

The  Canary  Island  date  palm  is  the  most  popular  palm  for  park 
or  street  planting,  being  more  hardy  than  the  true  date  palm,  larger 
and  more  vigorous  in  growth,  and  producing  no  suckers  from  the 
base  of  the  trunk.  Well-grown  specimens  in  the  California  coast 
districts  (region  2)  with  trunks  from  2  to  3  feet  thick  and  immense 
crowns  of  spreading  deep-green  leaves  are  among  the  most  imposing 
forms  of  plant  life.  The  leaflets  instead  of  radiating  from  one  point, 
as  in  fan  palms,  are  arranged  along  both  sides  of  a  common  stem  or 
midrib.  Palms  with  this  arrangement  of  leaves  are  called  pinnate 
palms.  Though  less  robust  in  other  regions,  the  species  is  very 
hardy  and  adapted  for  planting  anywhere  in  the  palm  belt  (regions 
3,5,  12,  and  13). 

The  true  date  palm  is  adapted  to  the  warmer  parts  of  regions  3 
and  5,  but  it  is  much  inferior  to  the  Canary  Island  species  for  orna- 
mental use  because  the  foliage  is  less  attractive,  owing  to  its  habit  of 
sending  out  suckers  from  the  base  of  the  trunk. 

THE  COCONUT  AND   ITS   RELATIVES. 

The  true  coconut  palm  is  confined  to  a  narrow  belt  along  the  coast 
of  southern  Florida,  but  other  species  of  Cocos  are  planted  in  the 
coast  districts  of  California.  The  species  that  is  most  prominent 
in  park  and  street  plantings  around  San  Diego,  Los  Angeles, 
and  Santa  Barbara  is  usually  known  as  Cocos  plumosa  or  Cocos 
romanzofficfria,  and  is  a  rather  tall,  slender  palm  with  a  long- jointed 
trunk  about  1  foot  in  diameter  and  long,  spreading,  feathery,  deep- 
green  leaves.  Another  series  is  represented  by  Cocos  yatay  and 
several  similar  species,  often  called  Cocos  austmlis  in  nursery  cata- 
logues. They  have  short,  thick  trunks,  grayish  or  bluish  foliage, 
and  fleshy  edible  fruits,  highly  flavored,  somewhat  like  pine- 
apples. These-  gray-leaved  species  are  very  hardy.  Another  coco- 
nut relative  is  the  Chilean  molasses  palm,  which  has  a  massive 
trunk  3  or  4  feet  in  diameter,  specimens  of  which  are  growing  at  a 
few  places  in  California. 

OTHER    PINNATE    PALMS. 

The  amethyst  palm,  a  native  of  Australia,  is  commonly  planted 
in  California.  It  usually  appears  in  lists  and  nursery  catalogues 
as  Seaforthia  elegans  or  Archontophoenix  alexandrae,  but  it  is  now 
recognized  as  distinct  from  both  of  these  species  and  has  received 
a  new  name,  Loroma  ametkystina.  Except  certain  species  of  Phoenix 
and  Cocos,  it  is  the  only  pinnate-leaved  palm  that  grows  freely  in 


Trees  for  Town  and  City  Streets. 


35 


the  open  air  in  the  coast  districts  of  California,  from  Santa  Barbara 
to  San  Diego.  In  habit  and  general  appearance  Loroma  is  more  like 
the  royal  palm,  though  with  a  smaller  trunk  and  fewer  leaves.  The 
pinkish  purple  drooping  flower  cluster  is  very  attractive  and  develops 
into  a  large  cluster  of  scarlet  berries. 

The  royal  palms,  species  of  Roystonea,  are  perhaps  the  most 
striking  ornamental  members  of  the  whole  group.  They  can  be 
grown  in  southern  Florida  and  even  exist  in  the  wild  state  in  some 
of  the  hammocks  below  Miami. 


PIG.  23. — California  pepper  trees,  Riverside,  Calif. 
PEPPER  TREE. 

The  California  pepper  tree  (fig.  23)  is  much  used  in  regions  2  and  3 
and  in  the  western  part  of  region  5.  It  is  a  moderate-sized,  broad- 
headed  tree  with  fine  foliage,  which  gives  it  a  light,  airy  appearance. 
During  the  fall  and  winter  it  is  covered  with  scarlet  berries,  which  in 
contrast  with  the  persistent  foliage  produce  a  pleasing  effect. 

POPLAR. 

Poplars  are  not  desirable  for  street  planting.  Their  wood  is 
easily  broken  by  ordinary  windstorms,  and  their  roots  run  near  the 
surface  and  are  likely  to  interfere  with  pavements,  as  shown  in 
figure  24,  while  those  of  some  varieties  are  especially  likely  to  make 


36 


Farmers'  Bulletin  i208. 


trouble  in  sewers  by  filling  them  with  a  mass  of  fibrous  roots  if 
access  is  once  gained.  Vigorous  root  growth  is  encouraged  by  the 
moisture  from  a  leak,  and  the  roots  ultimately  find  their  way  inside. 
The  mature  seed  is  carried  by  a  cottonlike  appendage,  and  in  many 
varieties  this  is  so  abundant  as  to  be  another  serious  objection  to  the 
planting  of  these  trees. 

The  southern  cottonwood,  Carolina  poplar,  and  the  northern  cot- 
tonwood  are  very  similar  in  their  adaptability  for  street-planting 
purposes.  They  are  easily  propagated,  easily  transplanted,  are  quick 
growing,  and  where  they  reach  maturity  under  normal  conditions 
form  very  large  oval-headed  handsome  trees,  but  under  the  artificial 
conditions  existing  in  cities  it  is  necessary  to  prime  them  quite  se- 


FIG.  24. — A  pavement  heaved  by  the  roots  of  poplar  trees. 

verely  when  young  to  remove  the  long  vigorous  growths  and  make 
the  heads  more  compact.  This  pruning  stimulates  more  vigorous 
growth,  which  must  be  removed  or  they  will  form  long  branches 
with  heavy  tops  that  are  especially  liable  to  injury  by  windstorms. 
The  more  they  are  pruned  the  greater  the  tendency  to  an  undesirable 
form  of  growth.  They  begin  dropping  their  leaves  early  in  the 
summer  and  lose  them  very  early  in  the  autumn.  Their  root  growth 
is  vigorous,  especially  in  the  presence  of  abundant  moisture.  Ex- 
cept in  regions  6,  7,  or  8,  or  in  locations  where  smoke  and  fumes  in 
the  air  prevent  the  growing  of  other  trees,  they  should  not  be 
planted. 

The  Lombardy  poplar  is  a  tall  columnar  tree  adapted  for  use  on 
very  narrow  streets.     (See  fig.  1.)     It  is  short  lived  in  many  places, 


Trees  for  Town  and  City  Streets.  37 

owing  largely  to  the  European  poplar  canker,  but  otherwise  is  a 
satisfactory  tree  for  these  conditions  in  all  parts  of  the  United 
States.  The  trees  may  be  planted  as  close  together  as  30  feet. 

None  of  the  other  poplars  have  much  to  recommend  them  for 
street  planting. 

RUBBER  TREE. 

The  rubber  tree  is  a  large-headed  handsome  evergreen,  suitable 
for  regions  3  and  5  and  the  southern  parts  of  regions  2  and  13  when 
the  use  of  an  evergreen  tree  is  warranted. 

SILK  OAK. 

The  silk  oak,  or  Australian  fern,  is  a  large,  handsome  tree  that 
succeeds  well  in  regions  2,  3,  and  13;  also  in  region  5  if  provided 
with  a  reasonable  amount  of  moisture,  as  it  stands  drought  remark- 
ably well.  It  is  covered  in  early  summer  with  orange-colored 
flowers. 

SWEET  GUM. 

The  sweet  gum  (fig.  25)  is  adapted  to  regions  11,  12,  and  13, 
especially  on  sandy  lands.  It  forms  an  oval-headed,  handsome  tree 
with  star-shaped  leaves  that  assume  a  particularly  brilliant  hue  in 
the  autumn.  It  is  better  adapted  to  suburban  conditions  than  to  the 
heart  of  a  city.'  Toward  the  northern  limits  of  its  successful  cultiva- 
tion it  is  difficult  to  transplant,  while  in  the  warmer  sections  of  the 
country  it  can  be  moved  with  comparative  ease.  It  should  be  trans- 
planted only  in  the  spring. 

SYCAMORE. 

The  sycamore,  also  called  the  buttonwood  and  buttonball  tree,  is 
a  large,  open,  spreading,  quick-growing  tree  native  along  water- 
courses. It  is  adapted  to  regions  1,  2,  3,  4,  9,  10,  11,  12,  and  13 
and  is  worth  testing  in  regions  5,  6,  7,  and  8.  Its  habit  of  shedding 
its  outer  bark  in  large  flakes,  leaving  the  white  new  bark  showing  in 
large  patches,  makes  it  a  conspicuous  tree  wherever  grown.  The 
fruits  are  balls  1  inch  or  more  in  diameter  and  are  sometimes  ob- 
jected to  because  they  make  dirt  when  falling;  also  the  shed  bark 
is  considered  objectionable.  It  is  such  a  strong-growing,  handsome 
tree  and  succeeds  so  well  under  city  conditions  that  it  is  being  planted 
more  and  more  frequently.  It  will  stand  more  pruning  and  shaping 
than  any  other  street  tree.  Without  pruning  it  is  too  large  for  ordi- 
nary streets  unless  spaced  at  almost  double  the  usual  planting  dis- 
tance, with  the  trees  staggered  along  the  street  instead  of  being 
planted  opposite.  Its  high  head  and  open  habit  of  growth  are  dis- 
tinct advantages  for  street  planting.  Its  foliage,  too,  is  a  light  green?j 


38 


Farmers'  Bulletin  1208. 


FIG.  25. — Sweet-gum  trees,  Washington,  D.  C. 


Trees  for  Town  and  Citi/  Streets. 


39 


which  gives  an  impression  of  airiness  with  the  shade.  It  is  subject 
to  attack  by  a  fungus  that  kills  the  leaves  while  still  small  or  par- 
tially mutilates  them,  giving  them  an  unsightly  appearance.  In 
some  places  this  trouble  is  rather  serious.  « 

The  California  sycamore  is  a  native  of  California,  adapted  to 
regions  1,  2,  3,  and  4,  and  portions  of  region  5.  It  is  similar  in  gen- 
eral characteristics  to  the  sycamore. 


FIG.  26. — London  plane  trees,  Washington,  D.  C. 

The  London  plane  tree  is  one  of  the  Old  World  forms  of  sycamore 
(fig.  26).  According  to  Alfred  Render,10  "the  true  oriental  plane  is 
rare  in  cultivation,  the  tree  usually  planted  under  this  name  being 
Platanus  acerifolia"  It  is  more  compact  in  habit  of  growth  and  has 
the  other  good  qualities  of  the  sycamore.  It  is  being  more  and  more 
used  on  city  streets  and  is  proving  satisfactory  in  regions  1,  2,  3,  4, 
9,  10,  11,  and  12.  It  will  probably  succeed  in  the  warmer  parts  of 
regions  6  and  7  and  also  in  regions  5  and  8.  It  is  a  more  desirable 
tree  for  ordinary  use  than  the  sycamore,  on  account  of  its  more 
compact  habit  and  comparative  freedom  from  disease,  though  it  is 
tender  in  the  northernmost  sections. 

10  Bailey,   L.   H.,   ed,     New  York,   1916.      Standard  Cyclopedia   of   Horticulture,   v.   5, 
p.  2707. 


40 


Farmers'  Bulletin  1208. 

TULIP  TREE. 


The  tulip  tree  is  also  sometimes  called  the  tulip  poplar  (fig.  27)  or 
yellow  poplar,  though  the  latter  names  are  unfortunate,  as  the  tree  is 
not  a  poplar  or  even  closely  related  to  the  poplars.  It  is  a  large, 
rapid-growing  tree  suitable  for  suburban  conditions  in  regions  1,  2, 
10,  11,  and  12.  The  leaves  are  of  unusual  form,  the  upper  half  ap- 
pearing to  have  been  cut  away,  leaving  a  notch  about  where  it  would 


FIG.  27. — Tulip  tn-os,  .some!  inn 


H),  D.  C. 


seem  the  middle  of  the  leaf  should  be.  The  color  is  a  light  green. 
The  roots  are  unusually  soft  and  tender,  and  therefore  the  tree  needs 
to  be  transplanted  quickly  and  with  great  care.  Small  sizes  should 
be  planted,  especially  near  the  northern  limits  of  growth.  It  should 
be  transplanted  only  in  the  spring.  If  after  transplating  it  the 
top  should  die  and  a  new  vigorous  shoot  should  put  out  from  the 
root,  it  would  be  desirable  to  form  a  new  top  from  this  shoot  rather 
than  to  transplant  another  tree. 


HOW  TO  DO  IT. 

DO  YOU  WANT  practical  suggestions  on 
how  to  build  a  silo,  a  hog  house,  a  poul- 
try house,  a  potato  storage  house,  or  how  to 
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convenience,  a  fly  trap,  or  a  self-feeder  for 
hogs?  Are  you  seeking  ideas  on  how  to  pre- 
pare vegetables  for  the  table,  how  to  care  for 
food  in  the  home,  how  to  bake  bread  and  cake, 
and  prepare  appetizing  foods  in  an  efficient 
and  economical  manner?  Is  there  some  prac- 
tical question  about  your  corn  or  wheat  or 
cotton  or  other  crops,  or  about  your  poultry 
or  live-stock,  to  which  you  are  seeking  an  an- 
swer? The  answers  to  thousands  of  such 
questions  and  practical  suggestions  for  doing 
thousands  of  things  about  the  farm  and  home 
are  contained  in  over  500  Farmers'  Bulletins, 
which  can  be  obtained  upon  application  to 
the  Division  of  Publications,  United  States 
Department  of  Agriculture,  Washington,  D.  C. 


WASHINGTON  :  GOVERNMENT  PRINTING  OFFICB  :  1923 


Gaylord  Bros. 

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PAT.  JAN.  21 ,1908 


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